Electronic throttle control hysteresis mechanism

CROSS-REFERENCE TO RELATED APPLICATIONS

Not Applicable

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

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REFERENCE TO MICROFICHE APPENDIX

Not Applicable

FIELD OF THE INVENTION

The present invention generally relates to a control pedal assembly for a motor vehicle and, more particularly, to a control pedal assembly for a motor vehicle which is electronically coupled and has a mechanical hysteresis device to simulate the feel of a control pedal assembly which is mechanically coupled.

BACKGROUND OF THE INVENTION

Control pedals are typically provided in a motor vehicle, such as an automobile, which are foot operated by the driver. Separate control pedals are provided for operating brakes and an engine throttle. When the motor vehicle has a manual transmission, a third control pedal is provided for operating a transmission clutch. The control pedals are typically connected to control devices by push-pull cables, rods, or other mechanical transmission devices which convert the limited rotary motion of the pedals into useful mechanical motion at the control devices to control operation of the motor vehicle. The engine throttle is typically connected to an accelerator pedal through a mechanical cable such as a Bowden cable. This mechanical linkage has a desirable and functional “feel” wherein the pressure required for advancing the control pedal to accelerate the motor vehicle is greater than the pressure required for maintaining the pedal in a fixed position to maintain the motor vehicle at a constant speed. This difference of required pressures is often referred to as a “hysteresis effect”. The pressure required to advance the control pedal is typically relatively high. This is desirable to obtain adequate return pressure to return the pedal to the idle position in a desired amount of time when foot pressure is removed from the control pedal. The pressure required to advance the control pedal is easily provided when accelerating but would become uncomfortable over time to maintain a relatively constant speed. Therefore, the hysteresis effect is important in providing a reasonable force for maintaining the accelerator pedal in position to comfortably drive at a generally constant speed while providing an adequate return force for returning the control pedal to idle to decelerate the motor vehicle.

There have been many attempts to introduce an electrical linkage between the control pedal and the control device. Typically, a position sensor converts the position of the control pedal into an electrical signal which is sent to the control device. This electrical linkage has far fewer routing limitations than the mechanical linkages. The control pedal, however, must be provided with a hysteresis device to obtain the “feel” of a control pedal having a mechanical linkage. Various proposals have been made to provide a control pedal with both an electrical linkage and a mechanical hysteresis device. While these proposed control pedals may adequately provide the “feel” of a control pedal with a mechanical linkage, they are relatively complex and expensive to produce. Additionally, the proposed control pedals require a relatively large amount of space. Accordingly, there is a need in the art for a control pedal assembly which is electronically coupled and has a mechanical hysteresis device, is relatively simple and inexpensive to produce, and/or is highly reliable in operation.

SUMMARY OF THE INVENTION

The present invention provides a control pedal assembly which overcomes at least some of the above-noted problems of the related art. According to the present invention, a control pedal assembly comprises, in combination, a support structure having a guide surface and a pedal arm carrying a pedal at a lower end of the pedal arm. The pedal arm is pivotable relative to the support structure about a pivot axis between a released position and an applied position. A hysteresis device is secured to an upper end of the pedal arm and engages the guide surface so that the hysteresis device moves along the guide surface as the pivot arm pivots between the released position and the applied position. A distance between the guide surface and the pivot axis varies so that the hysteresis device applies an increasing normal force to the guide surface to create an increasing friction force that opposes motion of the hysteresis device as the pedal arm pivots from the released position to the applied position.

According to another aspect of the present invention, an electronic control pedal assembly comprises, in combination, a support structure having a first guide surface and a second guide surface spaced apart from and facing the first guide surface and a pedal arm carrying a pedal at a lower end of the pedal arm. The pedal arm is pivotable relative to the support structure about a pivot axis between a released position and an applied position. A sensor is operably connected to the pedal arm and provides electronic signals responsive to pivotable movement of the pedal arm about the pivot axis. A hysteresis device is secured to the pedal arm and is engagable with the first and second guide surfaces so that the hysteresis device slides along the first and second guide surfaces as the pivot arm pivots between the released position and the applied position. A distance between the guide surfaces decreases in a direction of travel of the hysteresis device as the pedal arm pivots from the release position to the applied position so that an increasing interference between the support structure and the hysteresis device creates an increasing friction force that opposes sliding motion of the hysteresis device as the pedal arm pivots from the released position to the applied position.

According to yet another aspect of the present invention, an electronic control pedal assembly comprises, in combination, a support structure having a guide surface and a pedal arm carrying a pedal at a lower end of the pedal arm. The pedal arm is pivotable relative to the support structure about a pivot axis between a released position and an applied position. A sensor is operably connected to the pedal arm and provides electronic signals responsive to pivotable movement of the pedal arm about the pivot axis. A hysteresis device includes a plunger axially movable in a cavity formed in an upper end of the pedal arm and having an end engaging the guide surface and a spring member biasing the plunger toward the guide surface so that the end of the plunger slides along the guide surface as the pivot arm pivots between the released position and the applied position. A distance between the guide surface and the pedal arm decreases in a direction of travel of the hysteresis device as the pedal arm pivots from the release position to the applied position so that the plunger is depressed against the bias of the spring member to apply an increasing normal force to the guide surface and create an increasing friction force that opposes sliding motion of the plunger against the guide surface as the pedal arm pivots from the released position to the applied position.

From the foregoing disclosure and the following more detailed description of various preferred embodiments it will be apparent to those skilled in the art that the present invention provides a significant advance in the technology and art of control pedal assemblies. Particularly significant in this regard is the potential the invention affords for providing a high quality, reliable, low cost universal assembly. Additional features and advantages of various preferred embodiments will be better understood in view of the detailed description provided below.

BRIEF DESCRIPTION OF THE DRAWINGS

These and further features of the present invention will be apparent with reference to the following description and drawing, wherein:

<figref idref="DRAWINGS">FIG. 1</figref> is a perspective view of a control pedal assembly having a mechanical hysteresis device according to a first embodiment of the present invention;

<figref idref="DRAWINGS">FIG. 2</figref> is an exploded view of the control pedal assembly of <figref idref="DRAWINGS">FIG. 1</figref>;

<figref idref="DRAWINGS">FIG. 3</figref> is an enlarged, fragmented elevational view of the control pedal assembly of <figref idref="DRAWINGS">FIGS. 1 and 2</figref> in the area of the mechanical hysteresis device;

<figref idref="DRAWINGS">FIG. 4</figref> is an enlarged, fragmented elevational view of the control pedal assembly similar to <figref idref="DRAWINGS">FIG. 3</figref> showing operation of the mechanical hysteresis device as the pedal arm pivots with return springs removed for clarity;

<figref idref="DRAWINGS">FIG. 5</figref> is an exploded view of a control pedal assembly having a mechanical hysteresis device according to a second embodiment of the present invention;

<figref idref="DRAWINGS">FIG. 6</figref> is an enlarged, fragmented elevational view of the control pedal assembly of <figref idref="DRAWINGS">FIG. 5</figref> in the area of the mechanical hysteresis device; and

<figref idref="DRAWINGS">FIG. 7</figref> is an enlarged, fragmented elevational view of the control pedal assembly similar to <figref idref="DRAWINGS">FIG. 6</figref> showing operation of the mechanical hysteresis device as the pedal arm pivots with return springs and a hysteresis device spring removed for clarity.

It should be understood that the appended drawings are not necessarily to scale, presenting a somewhat simplified representation of various preferred features illustrative of the basic principles of the invention. The specific design features of a control pedal assembly as disclosed herein, including, for example, specific dimensions will be determined in part by the particular intended application and use environment. Certain features of the illustrated embodiments have been enlarged or distorted relative to others to facilitate visualization and clear understanding. In particular, thin features may be thickened, for example, for clarity or illustration. All references to direction and position, unless otherwise indicated, refer to the orientation of the control pedal assembly illustrated in the drawings. In general, up or upward refers to an upward direction within the plane of the paper in <figref idref="DRAWINGS">FIGS. 3 and 6</figref> and down or downward refers to a downward direction within the plane of the paper in <figref idref="DRAWINGS">FIGS. 3 and 6</figref>. Also in general, fore or forward refers to a direction toward the front of the motor vehicle, that is, a leftward direction within the plane of the paper in <figref idref="DRAWINGS">FIGS. 3 and 6</figref> and aft or rearward refers to a direction toward the rear of the motor vehicle, that is, a rightward direction within the plane of the paper in <figref idref="DRAWINGS">FIGS. 3 and 6</figref>.

DETAILED DESCRIPTION OF CERTAIN PREFERRED EMBODIMENTS

It will be apparent to those skilled in the art, that is, to those who have knowledge or experience in this area of technology, that many uses and design variations are possible for the improved control pedal assemblies disclosed herein. The following detailed discussion of various alternative and preferred embodiments will illustrate the general principles of the invention with reference to an electronic accelerator pedal for use with an automobile. Other embodiments suitable for other applications, such as brake or clutch pedals and/or other types of motor vehicles, will be apparent to those skilled in the art given the benefit of this disclosure. The present invention can be utilized with any vehicle having a foot operated control pedal including trucks, buses, vans, recreational vehicles, earth moving equipment and the like, off road vehicles such as dune buggies and the like, air borne vehicles, and water borne vehicles.

Referring now to the drawings, <figref idref="DRAWINGS">FIGS. 1</figref> to <b>3</b> show a control pedal assembly <b>10</b> for a motor vehicle according to the present invention which is selectively adjustable to a desired position by a driver. The control pedal assembly <b>10</b> includes a mounting bracket or support structure <b>12</b>, a pedal arm <b>14</b> pivotally connected to the mounting bracket <b>12</b> to be pivotable between a released position R and an applied position A, an electronic throttle control (ETC) sensor <b>16</b> operatively connecting to the pedal arm <b>14</b> to a control device to provide electrical control signals indicating pivotal movement of the pedal arm <b>14</b>, and a mechanical hysteresis device <b>18</b>.

The support structure <b>12</b> is sized and shaped for rigid attachment of the adjustable control pedal assembly <b>10</b> to a firewall or other suitable support member of the motor vehicle. The support structure <b>12</b> may be may be formed of any suitable material such as, for example, a plastic material such as nylon and may be formed in any suitable manner such as, for example, molding. The illustrated support structure <b>12</b> includes a housing member <b>20</b> and a cover member <b>22</b>. The illustrated housing member <b>20</b> has a planar side wall <b>24</b> and front, top, and rear walls <b>26</b>,<b>27</b>, <b>28</b> perpendicularly extending from front, top, and rear edges of the side wall <b>24</b> respectively. The illustrated cover member <b>22</b> is generally in the form of a plate sized to engage the walls <b>24</b>, <b>26</b>, <b>27</b>, <b>28</b> of the housing member <b>20</b>. The cover member <b>22</b> cooperates with the housing member <b>20</b> to form a hollow interior space <b>30</b> which is closed except for an open bottom. The illustrated cover member <b>22</b> is removably secured to the housing member <b>20</b> with mechanical fasteners <b>32</b> in the form of screws. It is noted, however, that the cover member <b>22</b> can be secured to the housing member <b>20</b> in any suitable alternative manner such as for example, adhesives, bolts, rivets, welds, clips, locks, snap-fit connections, or the like. The illustrated housing member <b>20</b> is provided with a pair of mounting tabs <b>34</b> having openings <b>36</b> therein for receiving mechanical fasteners to rigidly secure the support structure <b>12</b> to the motor vehicle. The openings <b>36</b> of illustrated mounting tabs <b>34</b> are each provided with a bushing <b>38</b>. It is noted that the support structure <b>12</b> can alternatively be secured to the motor vehicle in any other suitable manner.

Laterally extending from the side wall <b>24</b> of the housing member <b>20</b> within the interior space <b>30</b> is a first or upper guide wall or rail <b>40</b> and a second or lower guide wall or rail <b>42</b> below and spaced apart from the upper guide wall <b>40</b>. The guide walls <b>40</b>, <b>42</b> extend in the forward rearward direction from the front wall <b>26</b> to the rear wall <b>28</b> and in the lateral direction from the side wall <b>24</b> to a location spaced apart from the cover member <b>22</b> for passage of the pedal arm <b>14</b> between the cover member <b>22</b> and the guide walls <b>40</b>, <b>42</b>. The guide walls <b>40</b>, <b>42</b> are each arcuate or curved and are located above a pivot axis <b>44</b> of the pedal arm <b>14</b> such that they are concave relative to the pivot axis <b>44</b>. The bottom of the upper guide wall <b>40</b> forms a first or upper guide surface <b>46</b> and the top of the lower guide wall forms a second or lower guide surface <b>48</b>. The upper and lower guide surfaces <b>46</b>, <b>48</b> are spaced apart and facing each other. The upper and lower guide surfaces <b>46</b>, <b>48</b> are sized and shaped to cooperate with the mechanical hysteresis device <b>18</b> as described in more detail hereinafter. Preferably, at least a portion of at least one of the guide surfaces <b>46</b>, <b>48</b> is non-linear or arcuate. In the illustrated embodiment, both of the guide surfaces <b>46</b>, <b>48</b> are entirely nonlinear or arcute over the path of the hysteresis device <b>18</b>.

The pedal arm <b>14</b> is sized and shaped for pivotal attachment to the support structure <b>12</b>. The pedal arm <b>14</b> may be may be formed of any suitable material such as, for example, a plastic material like nylon and may be formed in any suitable manner such as, for example, molding. The illustrated pedal arm <b>14</b> is generally elongate and has an upper end forming a laterally extending opening <b>50</b> on one lateral side and a pivot pin <b>52</b> extending from the other lateral side and coaxial with the opening <b>50</b>. The pivot pin <b>52</b> and the opening <b>50</b> cooperate to form the laterally extending pivot axis <b>44</b> for the pedal arm <b>14</b>. The opening <b>50</b> is sized and shaped for receiving a pivot pin <b>54</b> laterally extending from the side wall <b>24</b> of the housing member <b>20</b> within the interior space <b>30</b>. The pivot pin <b>52</b> is sized and shaped for extending into the ETC sensor <b>16</b>. Mounted in this manner the upper end of the pedal arm <b>14</b> extends into the interior space <b>30</b> through the open bottom of the support structure <b>12</b> and is pivotably secured to the support structure <b>12</b> for rotation about the pivot axis <b>44</b>. It is noted that the pedal arm <b>14</b> can be pivotably secured to the support structure <b>12</b> in other suitable manners within the scope of the present invention.

The elongate pedal arm <b>14</b> extends generally downward from the pivot axis <b>44</b>. The lower end of the pedal arm <b>14</b> carries a pedal <b>56</b>. The pedal <b>56</b> of the illustrated embodiment is formed unitary with the pedal arm <b>14</b>, that is, molded of a single piece but the pedal <b>56</b> can alternatively be partially or fully formed of a separate piece or pieces and attached together.

The pedal arm <b>14</b> is operatively connected to the control device such as a throttle via the ETC sensor <b>16</b> so that pivotal movement of the pedal arm <b>14</b> about the pivot axis <b>44</b> operates the control device in a desired manner. The illustrated ETC sensor <b>16</b> is a rotational sensor adapted to sense rotation of the pedal arm <b>14</b>. The illustrated ETC sensor <b>16</b> secured to the support structure <b>12</b> at the cover member <b>22</b> through which the pivot pin <b>52</b> extends through an opening <b>58</b> to the ETC sensor <b>16</b> for cooperation therewith. The illustrated ETC sensor <b>16</b> is provided with a pair of openings <b>60</b> sized and shaped to receive a pair of pins <b>62</b> therein. The pins <b>62</b> laterally extend from the outer side of the cover member <b>22</b>. Mechanical fasteners <b>64</b> in the form of screws extend into the pins <b>62</b> to secure the ETC sensor <b>16</b> to the cover member <b>22</b>. It is noted that the ETC sensor alternatively can be secured to the support structure in any other suitable manner. It is also noted that the ETC sensor <b>16</b> can be any suitable rotational sensor known to those skilled in the art or can be any other suitable type of sensor known to those skilled in the art such as, for example, a force sensor adapted to sense the amount of force applied to the pedal arm <b>14</b>. The ETC sensor <b>16</b> is in electrical communication, such as connected via wires or wireless communication devices, with the control device to provide electrical signals indicating rotational movement of the pedal arm <b>14</b>.

The illustrated mechanical hysteresis device <b>18</b> includes a resilient spring member <b>66</b> carried by the upper end of the pedal arm <b>14</b> and engageable with both the upper and lower guide surfaces <b>46</b>, <b>48</b>. The illustrated spring member <b>66</b> is an extrusion formed by a wall forming an exterior surface and having a hollow interior open on lateral sides thereof. The spring member <b>66</b> has upper and lower engagement portions <b>68</b>, <b>70</b> sized and shaped for engaging the upper and lower guide surfaces <b>46</b>, <b>48</b> respectively. The illustrated engagement portions <b>68</b>, <b>70</b> are arcuate and convex at their exterior side. The engagement portions <b>68</b>, <b>70</b> are secured together at their forward and rearward ends by forward and rearward connecting portions <b>72</b>, <b>74</b>. The illustrated connecting portions <b>72</b>, <b>74</b> are in the form of vertically disposed planar walls. Formed in this manner, the spring member <b>66</b> is resiliently deformable as describe in more detail hereinafter.

The upper end of the pedal arm <b>14</b> is provided with a notch or seat <b>76</b> for receiving the spring member <b>66</b> which is located above the pivot axis <b>44</b>, that is, on the opposite side of the pivot axis <b>44</b> from the pedal <b>56</b>. The illustrated notch <b>76</b> is open at its forward and rearward sides and the lateral side facing the side wall <b>24</b> of the housing member <b>20</b> and is open at its top and bottom sides and the lateral side facing the cover member <b>22</b>. A top surface of the notch <b>76</b> is downward facing and is disposed above the upper guide wall <b>40</b>. A bottom surface of the notch <b>76</b> is upward facing and is disposed below the lower guide wall <b>42</b>. The spring member <b>66</b> is located between the upper and lower surfaces of the notch <b>76</b> so that the spring member <b>66</b> is located between the upper and lower guide walls <b>40</b>, <b>42</b>. The illustrated spring member <b>66</b> is secured to the pedal arm by two pairs of mounting tabs <b>78</b> engaging the connecting portions <b>72</b>, <b>74</b> of the spring member <b>66</b>. The mounting tabs <b>78</b> are each planar and extend laterally from the lateral side surface of the notch <b>76</b>. Each pair of mounting tabs <b>78</b> are sized and shaped to receive one of the spring member connecting portions <b>72</b>, <b>74</b> therebetween. With each of the connecting portions <b>72</b>, <b>74</b> extending between respective pairs of the mounting tabs <b>78</b>, the spring member <b>66</b> is held in place within the notch <b>76</b>.

Positioned between the upper and lower guide walls <b>40</b>, <b>42</b>, the spring member upper and lower engagement portions <b>68</b>, <b>70</b> respectively engage the upper and lower guide surfaces <b>46</b>, <b>48</b>. As the pedal arm <b>14</b> pivots, the spring member upper and lower engagement portions <b>68</b>, <b>70</b> slide along the upper and lower guide surfaces <b>46</b>, <b>48</b> respectively. The upper and lower guide surfaces <b>46</b>, <b>48</b> are sized and shaped so that the spring member <b>66</b> is compressed between the guide surfaces <b>46</b>, <b>48</b> as the spring member <b>66</b> moves rearward between the guide surfaces <b>46</b>, <b>48</b>. That is, the distance w₁, w₂between the guide surfaces <b>46</b>, <b>48</b> decreases in a rearward direction. Preferably, a distance d₁, d₂between at least one of the guide surfaces <b>46</b>, <b>48</b> and the pivot axis <b>44</b> varies so that the spring member <b>66</b> applies an increasing normal force to the guide surface <b>46</b>, <b>48</b> to create an increase friction force that opposes sliding motion of the spring member <b>66</b> as the pedal arm <b>14</b> pivots and moves the spring member <b>66</b> in a rearward direction. In the illustrated embodiment, the distance between each of the guide surfaces <b>46</b>, <b>48</b> and the pivot axis <b>44</b> varies in this manner.

Return springs <b>80</b>, <b>82</b> are located within the interior cavity <b>30</b> of the support structure <b>12</b> and are adapted to resiliently bias the pedal arm <b>14</b> to the fully rearward or undepressed position (shown in FIG. <b>3</b>). The illustrated first and second return springs <b>80</b>, <b>82</b> are coaxial helical coil compression springs of differing coil diameters. It is noted, however, that return springs <b>80</b>, <b>82</b> of other types can be utilized to urge or bias the pedal arm to the fully undepressed or idle position. The forward ends of the illustrated return springs <b>80</b>, <b>82</b> engage the upper end of the pedal arm <b>14</b> while the rearward ends of the illustrated return springs <b>80</b>, <b>82</b> engage the interior surface of the rear wall <b>28</b> of the housing member <b>20</b>. It is noted that the control pedal assembly <b>10</b> can operate with only one of the return springs <b>80</b>, <b>82</b> but the other one of the return springs <b>80</b>, <b>82</b> is provided for redundancy as a protection against spring failure and/or more desirable sizing of the return springs.

Installed in this manner, the return springs <b>80</b>, <b>82</b> engage the forward side of the pedal arm <b>14</b> near and above the pivot axis <b>44</b> to bias the pedal arm <b>14</b> to an idle position when no pressure is applied to the pedal. During operation of the motor vehicle, the operator depresses the pedal <b>56</b> using a foot to control the motor vehicle. The pressure on the pedal <b>56</b> pivots the pedal arm <b>14</b> about the pivot axis <b>44</b> against the bias of the return springs <b>80</b>, <b>82</b>. As the pedal arm <b>14</b> rotates, the ETC sensor <b>16</b> detects the rotation and sends electrical signals indicating the magnitude of rotation to the control device to control the motor vehicle. As the pedal arm <b>14</b> rotates, the pedal arm <b>14</b> moves the spring member <b>66</b> rearward along the upper and lower guide surfaces <b>46</b>, <b>48</b>. As best shown in <figref idref="DRAWINGS">FIG. 4</figref>, the engagement portions <b>68</b>, <b>70</b> are resiliently squeezed together or forced toward one another by the wedge action provided by the guide surfaces <b>46</b>, <b>48</b> as the spring member <b>66</b> slides rearward along the guide surfaces <b>46</b>, <b>48</b>. It is noted that the wedge action creates an increasing normal force acting on the guide surfaces <b>46</b>, <b>48</b> by the spring member <b>66</b>. This increasing normal force generates increasing friction between the spring member <b>66</b> and the guide surfaces <b>46</b>, <b>48</b>. It is noted that the materials of the spring member <b>66</b> and the guide surfaces <b>46</b>, <b>48</b> are selected to obtain desired friction. Preferably, there is plastic to plastic contact to obtain the desired friction. It should be appreciated by one skilled in the art that differing requirements of the control pedal assembly <b>10</b> can be met by, for example, varying the location and shape of the guide walls <b>40</b>, <b>42</b>, the force provided by the spring member <b>66</b>, and/or other variables. When pressure is maintained on the pedal <b>26</b>, the friction between the spring member <b>66</b> and the guide surfaces <b>46</b>, <b>48</b> assists in maintaining the pedal arm <b>14</b> in its current position. Increased pressure is required on the pedal <b>56</b> to overcome the increasing friction and further advance the pedal <b>56</b>. As the spring member <b>66</b> is compressed, it is preferably wedged in an inward direction with increasing force so that the hysteresis device <b>18</b> provides variable friction. When pressure is removed from the pedal <b>56</b>, the return springs <b>80</b>, <b>82</b> resiliently return the pedal arm <b>14</b> to the idle position. As the pedal arm <b>14</b> returns, the spring member <b>66</b> slides forward along the guide walls <b>40</b>, <b>42</b> and resiliently decompresses to maintain engagement with the guide walls <b>40</b>, <b>42</b> with decreasing force.

<figref idref="DRAWINGS">FIGS. 5</figref> to <b>7</b> illustrate a control pedal assembly <b>100</b> according to a second embodiment of the present invention wherein like reference numbers are utilized for like structure. The control pedal assembly <b>100</b> according to the second embodiment of the invention is substantially similar to the control pedal assembly <b>10</b> according to the first embodiment of the invention except that the mechanical hysteresis device <b>18</b> is in a different form.

The illustrated mechanical hysteresis device <b>18</b> includes a plunger <b>102</b> and a resilient spring member <b>104</b> biasing the plunger <b>102</b>. The plunger and spring member <b>102</b>, <b>104</b> are each carried by the upper end of the pedal arm <b>14</b> above the pivot axis <b>44</b>. The plunger <b>102</b> has an engagement portion <b>106</b> sized and shaped for engaging a guide surface <b>108</b> and a guide portion <b>110</b>. The illustrated engagement portion <b>106</b> is generally in the form of a block having arcuate upper surface. The illustrated guide portion <b>110</b> is in the form of a hollow tube downwardly extending from the lower surface of the engagement portion. The illustrated spring member <b>104</b> is a helical coil compression spring sized and shaped to be disposed within the guide portion <b>110</b> and engaging the lower surface of the engagement portion <b>106</b> to bias the plunger <b>102</b> as described in more detail hereinafter. It is noted that the spring member <b>104</b> can take many different forms within the scope of the present invention such as, for example, a leaf spring, a block spring, a helical-coil tension spring, a fluid spring, or the like.

The upper end of the pedal arm <b>14</b> is provided with an annular-shaped opening or cavity <b>112</b> sized and shaped for closely receiving the guide portion <b>110</b> of the plunger <b>102</b> therein for sliding movement of the plunger <b>102</b> into and out of the opening <b>112</b>. The pedal arm <b>14</b> is preferably provided with a seat <b>114</b> for receiving the spring member <b>104</b> that is located within the opening <b>112</b>. The guide portion <b>110</b> of the plunger <b>102</b> is positioned within the opening <b>112</b>. The spring member <b>104</b> is positioned within the guide portion <b>110</b> of the plunger <b>102</b> and acts between the pedal arm seat <b>114</b> and the plunger engagement portion <b>106</b> to resiliently bias the plunger <b>102</b> in a direction out of the opening <b>112</b> and toward the guide surface <b>108</b>. The illustrated guide surface <b>108</b> is formed by the bottom of the top wall <b>27</b> of the housing member <b>20</b>. It is noted that alternatively a separate guide wall can be provided to form the guide surface <b>108</b>.

Positioned between the pedal arm <b>14</b> and the guide surface <b>108</b>, the spring biased plunger <b>102</b> resiliently engages the guide surface <b>108</b>. As the pedal arm <b>14</b> pivots, the plunger engagement portion <b>106</b> slides along the guide surface <b>108</b>. The guide surface <b>108</b> is sized and shaped so that the plunger <b>102</b> is compressed against the bias of the spring member <b>104</b> as the plunger <b>102</b> moves rearward along the guide surface <b>108</b>. That is, the distance d₁, d₂between the guide surface <b>108</b> and the pivot axis <b>44</b> decreases in a rearward direction so that the plunger <b>102</b> applies an increasing normal force to the guide surface <b>108</b> to create an increase friction force that opposes sliding motion of the plunger <b>102</b> as the pedal arm <b>14</b> pivots and moves the plunger <b>102</b> in a rearward direction.

Installed in this manner, the return springs <b>80</b>, <b>82</b> engage the forward side of the pedal arm <b>14</b> near and above the pivot axis <b>44</b> to bias the pedal arm <b>14</b> to an idle position when no pressure is applied to the pedal <b>56</b>. During operation of the motor vehicle, the operator depresses the pedal <b>56</b> using a foot to control the motor vehicle. The pressure on the pedal <b>56</b> pivots the pedal arm <b>14</b> about the pivot axis <b>44</b> against the bias of the return springs <b>80</b>, <b>82</b>. As the pedal arm <b>14</b> rotates, the ETC sensor <b>16</b> detects the rotation and sends electrical signals indicating the magnitude of rotation to the control device to control the motor vehicle. As the pedal arm <b>14</b> rotates, the pedal arm <b>14</b> moves the plunger <b>102</b> rearward along the guide surface <b>108</b>. As best shown in <figref idref="DRAWINGS">FIG. 7</figref>, the plunger <b>102</b> is resiliently depressed against the bias of the spring member <b>104</b> by the wedge action provided by the guide surface <b>108</b> as the plunger <b>102</b> slides rearward along the guide surface <b>108</b>. It is noted that the wedge action creates an increasing normal force acting on the guide surface <b>108</b> by the plunger <b>102</b>. This increasing normal force generates increasing friction between the plunger <b>102</b> and the guide surface <b>108</b>. It is noted that the materials of the plunger <b>102</b> and the guide surface <b>108</b> are selected to obtain desired friction. Preferably, there is plastic to plastic contact to obtain the desired friction. It should be appreciated by one skilled in the art that differing requirements of the control pedal assembly <b>100</b> can be met by, for example, varying the location and shape of the guide wall <b>108</b>, the size and shape of the plunger <b>102</b>, the force provided by the spring member <b>104</b>, and/or other variables. When pressure is maintained on the pedal <b>56</b>, the friction between the plunger <b>102</b> and the guide surface <b>108</b> assists in maintaining the pedal arm <b>14</b> in its current position. Increased pressure is required on the pedal <b>56</b> to overcome the increasing friction and further advance the pedal <b>56</b>. As the plunger <b>102</b> is depressed, it is preferably moved inward with increasing force so that the hysteresis device <b>18</b> provides variable friction. When pressure is removed from the pedal <b>56</b>, the return springs <b>80</b>, <b>82</b> resiliently return the pedal arm <b>14</b> to the idle position. As the pedal arm <b>14</b> returns, the plunger <b>102</b> slides forward along the guide surface <b>108</b> and the spring member <b>104</b> resiliently biases the plunger <b>102</b> outward to maintain engagement between the plunger <b>102</b> and guide surface <b>108</b> with decreasing force.

From the above description, it should be appreciated that the present invention provides a control pedal assembly <b>10</b>, <b>100</b> which is relatively simple and inexpensive to produce and is highly reliable in operation. It should also be appreciated that the various features of each illustrated embodiment can be utilized with the other illustrated embodiments.

From the foregoing disclosure and detailed description of certain preferred embodiments, it will be apparent that various modifications, additions and other alternative embodiments are possible without departing from the true scope and spirit of the present invention. For example, it will be apparent to those skilled in the art, given the benefit of the present disclosure, that the control pedal assembly be an adjustable pedal assembly wherein a drive assembly selectively adjusts the disclosed control pedal assembly in a forward/rearward direction relative to the steering wheel/seat of the motor vehicle. The embodiments discussed were chosen and described to provide the best illustration of the principles of the present invention and its practical application to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the present invention as determined by the appended claims when interpreted in accordance with the benefit to which they are fairly, legally, and equitably entitled.